A plasma display panel (hereinafter referred to as a PDP or simply a panel) is a display device with an excellent visibility and a large screen, and has a low-profile and lightweight body. The difference in discharging divides PDPs into two types of the alternating current (AC) type and the direct current (DC) type. In terms of the structure of electrodes, the PDPs fall into the 3-electrode surface discharge type and the opposing discharge type. In recent years, the dominant PDP is the AC type 3-electrode surface discharge PDP by virtue of having higher resolution and easier fabrication.
Generally, the AC type 3-electrode surface discharge PDP contains a front substrate and a back substrate disposed opposite from each other, and a plurality of discharge cells therebetween. On a front glass plate of the front substrate, scan electrodes and sustain electrodes, as display electrodes, are arranged in parallel with each other, and a dielectric layer and a protecting layer are formed over the display electrodes to cover the display electrodes. On the other hand, on a back glass plate of the back substrate, data electrodes are disposed in a parallel arrangement, and a dielectric layer is formed over the data electrodes to cover the data electrodes. On the dielectric layer between the data electrodes, a plurality of barrier ribs are formed in parallel with the rows of the data electrodes. Furthermore, a phosphor layer is formed between the barrier ribs and on the surface of the dielectric layer covering the data electrodes. The front substrate and the rear substrate are sealed with each other so that the display electrodes are orthogonal to the data electrodes in the narrow space between the two substrates. The narrow space, i.e., a discharge space, is filled with a discharge gas. The panel is thus fabricated.
Such a panel fabricated in this manner, however, generally exhibits a high voltage at the start of discharging, and the discharge itself is in an unstable condition. The panel is therefore aged in the manufacturing process to obtain consistent and stable discharge characteristics.
A conventional method has been employed for aging panels in which an anti-phased rectangular wave, that is, a voltage having an alternate (i.e., alternating) voltage component, is applied to a display electrode, i.e., between a scan electrode and a sustain electrode for a long period of time. To shorten the aging time, some methods have been suggested. For example, Japanese Patent Non-Examined Publication No. H07-226162 introduces a method in which a rectangular wave is applied, via an inductor, to the electrodes of a panel. On the other hand, Japanese Patent Non-Examined Publication No. 2002-231141 suggests a method as a combination of two kinds of discharging. According to the method, a pulse voltage having different polarity is placed between a scan electrode and a sustain electrode (i.e., discharging in the same surface) and consecutively, a pulse voltage having different polarity is now placed between the display electrodes and the data electrodes (i.e., discharging between the opposite surfaces).
Performing an aging process, as is known in the art, thins the surface of the protecting layer due to sputtering. However, an excessively strong aging provides the surface of the protecting layer with an excessive sputtering, thereby shortening the panel life.
The present invention addresses the problem described above. It is therefore an object of the invention to provide a long-life panel with minimized aging and an efficient aging method.